WATER-BLOCK filter removes water from gasoline and diesel fuel. Water-absorbing polymers trap water, restricting fuel flow when it is time to replace the element. Removes microscopic particles (17 microns) of rust, sand, dirt, scale and line. Also compatible with biodiesel blends up to 20%. Zinc die-cast top cap with 1 inch NPT pipe fittings. See-Thru bowl allows for visual monitoring of fuel flow. Maximum recommended flow rate is 25 gpm. Gravity flow rate is approximately 5 gpm with a 24 inch head. Working pressure up to 150 psi.